The present invention is concerned with an apparatus capable of selectively performing several operations relating to rivets, more particularly, a first operation in which improper setting of a self-piercing rivet is corrected, a second operation in which a self-piercing rivet is removed from workpieces, and a third operation in which a solid rivet is set, in place of a removed self-piercing rivet, for example.
A self-piercing rivet comprises a large-diameter head and a hollow shaft extending from the head. Riveting apparatus for joining workpieces by means of self-piercing rivets includes a punch and a cooperable die. The punch engages the head of the rivet and presses the shaft of the rivet through workpieces toward the die, which spreads the shaft to set the rivet.
Self-piercing rivets are used in the automotive industry, for example, to join pieces of sheet material. When properly set, the head of a rivet is pressed into a first workpiece, almost flush with a surface thereof, and leg portions of the shaft of the rivet pierce a second workpiece and are spread apart while remaining therein. Because no rivet penetration hole is formed in an exposed surface of the latter workpiece, there is no appearance impairment and no opening through which water or sound, for example, can penetrate.
There are occasions in which a self-piercing rivet is improperly set and in which it is desired to correct the setting. There are other occasions in which it is desired to remove a self-piercing rivet and to replace it with a solid rivet. There are prior art apparatuses for performing some of these functions, but not for performing all of these functions conveniently in a single apparatus. See, for example, Laid-open Utility Model Application No. S62-6943/1987 Gazette (Published Utility Model No. H3-31466/1991 Gazette) and Laid-open Utility Model Application No. H5-93639/1993 Gazette (Published Utility Model No. H7-47161/1995 Gazette) disclosing tools for removing solid rivets set in workpieces; U.S. Pat. No. 4,365,401 disclosing a tool capable of removing solid rivets set in workpieces, and also capable of setting solid rivets in workpieces; and Published Japanese Translation of Patent, No. H9-500059/1997 Gazette (corresponding to U.S. Pat. No. 5,722,144) disclosing a tool capable of removing self-piercing rivets set in workpieces and also capable of setting solid rivets in workpieces after self-piercing rivets have been removed.